VIENNA - The U.N. atomic watchdog signalled on Monday it would press Tehran for access to a military facility where it suspects Iran has built a chamber for high-explosive tests that could serve to develop nuclear weapons.
Iran, which rejects Western accusations it seeks nuclear arms, has so far resisted requests by the International Atomic Energy Agency to visit the extensive Parchin complex southeast of Tehran. The issue was expected to be raised during a high-level May 14-15 meeting in Vienna between Iran and the IAEA.
"It is important now ... that Iran let us have access to people, documents, information and sites," IAEA Deputy Director General Herman Nackaerts told reporters as he arrived for the talks at an Iranian diplomatic mission in Austria's capital.
His team left the building after about five hours, declining any comment to media waiting outside. The meeting would resume on Tuesday, an IAEA spokeswoman said.
An IAEA report last November found Iran had built a large containment vessel in 2000 at the Parchin site in which to conduct tests that the U.N. agency said were "strong indicators of possible (nuclear) weapon development".
It said a building was constructed "around a large cylindrical object". A large earth berm between the building containing the cylinder and a neighbouring building indicated the probable use of high explosives in the chamber.
The IAEA said it had obtained satellite images that were consistent with this information. The vessel was designed to contain the detonation of up to 70 kg of high explosives.
Israel - widely believed to hold the Middle East's only nuclear arsenal - and the United States have not ruled out military action to prevent Iran from obtaining atomic bombs if negotiations fail to achieve this peacefully.
Western diplomats say they suspect Iran is now cleaning the location to remove incriminating evidence.
A U.S. security institute said last week satellite imagery showed activity there which it said raised concern that Iran may be "washing" the building the IAEA wants to see.
A Western diplomat told Reuters he had seen other images also suggesting a clean-up operation at Parchin, including a stream of water apparently coming from the building.
Iran's Foreign Ministry spokesman has dismissed the allegations, saying nuclear activities cannot be washed away.
But the Institute for Science and International Security (ISIS), the Washington-based think-tank which published the satellite image last week, said this was incorrect.
"The concern is that washing could be incorporated into an effort to cleanse the building. The process could involve grinding down the surfaces inside the building, collecting the dust and then washing the area thoroughly. This could be followed with new building materials and paint," it said.
Nackaerts, head of the IAEA's nuclear inspections worldwide, said Iran must now engage on substance with the agency in its investigation into Iran's nuclear work, after several years of stonewalling.